a. Field of the inventions:
The present invention relates to a wide-angle photographic lens system and, more particularly, to a compact wide-angle photographic lens system with a short overall length.
B. Description of the prior art:
TO DESIGN A LENS SYSTEM WITH A SHORT OVERALL LENGTH OF A THREE-COMPONENT FOUR-ELEMENT LENS CONFIGURATION OR SO FOR WHICH ABERRATIONS ARE CORRECTED FAVOURABLY, IT IS KNOWN TO FORM, FOR EXAMPLE, THE SURFACE ON THE OBJECT SIDE OR ON THE IMAGE SIDE OF ITS THIRD LENS COMPONENT AS AN ASPHERICAL SURFACE OR TO FORM BOTH OF SAID SURFACES OF SAID THIRD LENS COMPONENT AS ASPHERICL SURFACES. Generally, however, it is considerably difficult to manufacture aspherical lenses. Especially, it is very difficult to form a curved surface of a small radius of curvature as an aspherical surface.